411 

 Tetragxmiceps Seotti, G. 0. Sars (new name) 



(Suppl. PI. 36 & 37, fig. 1). 



Tetragon iceps malleolata, Th. Scott, Additions to the Fauna of the Firth of Forth, Part IV. 

 10th Ann. Rep. of the Fishery Board for Scotland, p. 2:"W, PI. VIII, figs. 11 & 12 (not Brady). 



Specific Characters. Female. Body very slender and slightly tapered 

 behind, with the anterior and posterior divisions of about equal length. Cephalic 

 segment about as long as the 3 succeeding segments combined, and having the 

 lower edges angularly curved in the middle, rostral prominence short, evenly rounded 

 at the tip. Epimeral plates of the 3 succeeding segments small, rounded; last segment 

 scarcely shorter than the preceding one. Urosome rather narrow, with the segments 

 unarmed at the hind edges; last segment fully as large as the preceding one, and 

 having the anal opercle somewhat prominent and finely denticulated at the edge. 

 Caudal rami about the length of the anal segment and slightly dilated at the base, 

 outer edge with 2 successive slender bristles, dorsal bristle issuing in front of the 

 middle; apical seta simple and not very elongated. Anterior antennae about the 

 length of the cephalic segment, and composed of 9 well-defined joints, 1st joint 

 attaining almost half the length of the antenna, terminal part scarcely exceeding 

 Vs of the length of the proximal part. Posterior antennae rather slender, but 

 having the distal joint comparatively short, outer ramus very small, with 3 setae, 

 2 apical and one lateral. 1st pair of legs comparatively slender, outer ramus 

 shorter than the proximal joint of the inner, and having the last joint much smaller 

 than the others and armed at the tip with 2 spines and 2 geniculate setae ; 

 proximal joint of inner ramus narrow linear in form, ciliated on both edges and 

 carrying inside, behind the middle, a plumose seta, distal joint not attaining half 

 the length of the proximal one, and armed at the tip with a slender claw-like 

 spine and a still longer seta accompanied inside by a small bristle. The 2 suc- 

 ceeding pairs of legs with the inner ramus a little shorter than the outer, and 

 having the distal joint slender linear in form, with no seta inside, but with a 

 slender spine and one or 2 bristles at the tip. 4th pair of legs with the outer 

 ramus more than twice as long as the inner, and provided at the end with a 

 bunch of setae, 2 of which are remarkably strong and minutely spinulose at the 

 edges. Last pair of legs with the distal joint well defined and very slender, 

 gradually tapered towards the end and edged with a number of very small hair- 

 like bristles, one of which issues from the narrowly exserted tip ; proximal joint 

 somewhat lamellar and forming inside a triangular expansion extending about to 

 the middle of the distal joint and carrying 4 short setae, 3 inside and one at the tip. 



Male much smaller than female, and having the anterior antennae trans- 

 formed in the usual manner. Last pair of legs, as in the female, with the distal 



